Polyamides and polyimides are important engineering plastics. Since these kinds of plastic materials have excellent mechanical properties and thermal stability, they have been applied widely in the semiconductor industry, photoelectric industry, aviation industry, biomedical material industry, automobile industry, communication material industry, engineering industry and thin-film manufacturing industry. However, since the polyimide, which has excellent electrical property, is also applied in the basal material of the semiconductor and the packing substance, it becomes one of the most important materials for the high-technology industry.
Polyamides and polyimides are hard to be processed due to their high softening temperature, so they cannot be processed via the heating method. On the other hand, polyamides and polyimides with poor solubility can hardly be dissolved in organic solvents for easy processing. Therefore, most of the polyamides and polyimides are difficult to process.
Taking Kevlar as an example, which is a commercial product produced by DuPont Corporation US, since it could only be dissolved in the high polar solvents; the processing method for Kevlar is limited. It is inconvenient to process most kinds of the polyimides. For example, Kapton produced by DuPont Corporation US, which has a high softening temperature, is synthesized via a two-step method including the thin film manufacturing method and the wire coating method. The thin film, which is the precursor of polyimide formed by casting the poly(amic acid) solution, is formed as the membrane of polyimide after cyclodehydration procedure. Kapton is hard to be processed due to a high softening temperature and poor solubility (only soluble in concentrated sulfuric acid). In order to increase the processability and the application field of the polymers, solubility is very important issue preparation of polyamides and polyimides with better solubility becomes important.
Therefore, the present invention provides the synthetic methods for preparing the polyamides and polyimides with better physical and chemical properties (excellent solubility, lower dielectric constant, excellent thermal stability, excellent mechanical properties excellent processability, excellent optical property and decreasing water absorption) so as to overcome the drawbacks of the prior art described above.